The invention relates to a closing system for an instrument passage particularly for use in laparoscopic incision devices and for a closing instrument and cleansing ducts. Various closing systems for instrument passages are known and operating on different principles. Said known closing systems exhibit the following disadvantages:
The closing system known as a "trumpet valve" has to be operated manually when an instrument is inserted and has to be disassembled for cleaning. The manufacture of the "trumpet valve" is expensive and its components require high precision in manufacture. The closing system known as an automatic flap valve includes a flap mounted on a thin axle, said flap is set into the closing position by means of a spring. It is complicated to clean the flap mounted as described hereinbefore. A damaging of the front lens of an endoscope cannot be excluded when the latter is rapidly passed through.
The utility model DE-GM 74 30 345 discloses a closing system in which a flap is pivotally seated, which flap is set into the closing position by a permanent magnetic means. Cleaning is as difficult as in the foregoing devices.
The German patent specification DE 32 42 870 A1 discloses a closing system, one embodiment of which provides a laterally and pivotally seated flap which includes an annular magnet which cooperates with an annular magnet to a flap mount. In order to protect instruments against damage, when passed through, the flap is coated with plastics. This solution has the disadvantage, as concerns the non-pivotally seated flap embodiments, if ferro-magnetic instruments are passed it might occur that the latter takes the flap along. This is on the one hand an obstacle to the operator and, on the other hand, does not ensure a safe closing of the flap after the retraction of the instrument. Furthermore in the Patent specification DE 28 00 607 A1 an operation laparoscope is described in which the closing is effected by means of a ferro-magnetic sphere which is attracted by an annular magnet in the valve-seating so that the ferro-magnetic sphere if funneled into a cone-shaped valve seat. When, in this solution, instruments having a plane front face are passed, an entire disarrangement of the sphere may very easily occur so that a safe closing is not ensured after the retraction of the instrument. In order to prevent such a disarrangement, the aforementioned specification requires the use of instruments being provided with specially shaped front faces which laterally displace the sphere in the cone-shaped seat and which require protection means for the optical systems of, for example, an endoscope. Such measures involve considerable technical expenditures. However, optical systems of conventional endoscopes can be damaged by the aforesaid solution just as with conventional sphere valves. A closing system as shown in DE 28 00 607 A1 can be easily cleaned, out is bulky. The entire system is heavy due to the large mass of the sphere which, in turn, requires a high magnetic force.